1. Field of the Invention
The field of the present invention is traction control systems for vehicles, comprising driven wheel speed calculating means for calculating a speed of a driven wheel of the vehicle, a vehicle speed calculating means for calculating a vehicle speed of the vehicle, and a slip rate calculating means for calculating a slip rate of the driven wheel on the basis of the driven wheel speed and the vehicle speed, such that the feed-back control of a throttle valve is carried out to reduce the output torque from an engine to inhibit the excessive slipping of the driven wheel, when the slip rate exceeds a predetermined threshold value.
2. Description of the Prior Art
There is such a conventionally known traction control system described, for example, in Japanese Patent Application Laid-open No.60331/86.
In the prior art traction control system, however, when the feed-back control of the throttle valve is started as the slip rate of the driven wheels exceeds the predetermined threshold value, a fixed throttle opening degree previously set as an initial throttle opening degree, or a throttle opening degree determined from a slip acceleration of the driven wheels and an engine torque is used. For this reason, the prior art traction control system is accompanied by a problem that the operational state of the vehicle is not sufficiently reflected, and at the start of the feed-back control of the throttle valve, the behaviour of the vehicle is abruptly changed to cause a sense of incompatibility to the feeling of steering.